Currently, aluminum is welded mainly through arc welding methods, such as, for example, metal inert gas (“MIG”) welding or wolfram inert gas (“WIG”) welding, and, to an increasing extent, also through laser processing.
During laser welding of aluminum, generally high laser power has been required (e.g., for a CO2 laser, a laser power of more than 4 KW must be used) because the aluminum has a high reflectivity and a low absorption compared to steel. Also, an oxide layer (e.g., Al2O3) that is generally present on the surface of an aluminum workpiece has a considerably higher melting point than pure aluminum, which results in a barrier for the introduction of thermal energy into the basic workpiece body of pure aluminum. Furthermore, because aluminum is a good thermal conductor, thermal energy introduced by the laser beam is quickly dissipated from the site where the laser beam strikes the workpiece, such that additional energy is required to maintain a melting bath in a liquid state.